Electron beam applying apparatus and drawing apparatus

ABSTRACT

An electron beam applying apparatus includes: a thermal field emission type electron source emitting an electron beam; an electrostatic lens disposed immediately below the electron source and acting as a condensing electrode for condensing the electron beam in a first angular aperture emitted by the electron source in a second angular aperture smaller than the first angular aperture; a condenser lens disposed on a downstream side of the electrostatic lens and condensing the electron beam condensed in the second aperture angel by the electrostatic lens in a crossover point; and an objective lens disposed on a downstream side of the condenser lens and condensing the electron beam condensed in the crossover point by the condenser lens on the surface of the material.

TECHNICAL FIELD

The present invention relates to an electron beam applying apparatusapplying an electron beam on a surface of a material for recordinginformation on the surface of the material, and a drawing apparatusrecording information on a surface of a material with the use of anelectron beam applied by the electron beam applying apparatus.

BACKGROUND ART

Currently, a DVD (digital versatile disk), which is an optical recordingmedium having a large storage capacity for which data writing orre-wiring is allowed, exists. A storage capacity of a current DVD-R(recordable) or a DVD-RW (re-writeable) is 4.7 GB (gigabytes) for oneside in a single layer, and it has a pattern dimension in which a groovewidth is on the order of 400 nm, and a track pitch (a width betweengrooves) is on the order of 740 nm.

In contrast thereto, as a next-generation DVD, an HD-DVD (highdefinition DVD) exists. A storage. capacity of HD-DVD is on the order of15 GB for one side in a single layer, has a groove width on the order of200 through 300 nm, and a track pitch on the order of 600 nm. Further, astorage capacity of a Blu-ray Disk is on the order of 23 through 27 GBfor one side in a single layer, has a groove width on the order of 140through 170 nm, and a track pitch on the order of 320 nm.

Further, a further-next-generation DVD is expected as having a storagecapacity on the order of 50 through 100 GB for one side in a singlelayer. Its groove width may be less than 100 nm, and its track pitch maybe on the order of 200 through 300 nm.

For a current DVD, data writing is carried out with an optical masteringapparatus such as a LBR (laser beam recording apparatus). Also for anext-generation HD-DVD, it is expected that writing with an opticalmastering apparatus can be made. However, since a pit pattern of anext-generation Blu-ray Disk or a pattern dimension of afurther-next-generation DVD is very small, data writing cannot becarried out by an optical mastering apparatus.

Accordingly, in order to write data in a next-generation Blu-ray Disk ora further-next-generation DVD, an electron beam mastering apparatus suchas an EBR (electron beam recording apparatus) or such generating anelectron beam with a very small beam diameter with a large electriccurrent is required. For example, an electron beam mastering apparatusgenerating an electron beam with a beam diameter not more than 70 nm,with a large electric current of not less than 400 nA is required.

With reference to FIG. 5, an electron beam applying apparatus in therelated art is described.

In an electron beam applying apparatus shown in FIG. 5, an electron beamemitted from an electron source 52 undergoes correction for an axisshift thereof, passes thorough a hole part of a selector aperture(blanking aperture) 60, and after that, is condensed in a crossoverpoint CP by a condenser lens 58. Then, the electron beam from thecrossover point CP passes through a hole part of an objective aperture61, undergoes correction for astigmatism thereof by means of anastigmatism correction coil 62, undergoes correction for a focus thereofby means of an objective lens 66, and is condensed on a surface of amaterial 70.

When information is written on the material 70, turning on/off of theelectron beam emitted by the electron source 52 is controlled byblanking electrodes 54 and the selector aperture 60. Further, theelectron beam having passed through the hole part of the selectoraperture 60, the condenser lens 58 and the hole part of the objectiveaperture 61 and applied to the objective lens 66 is deflected byelectrostatic deflection electrodes 64 according to information to bewritten, and thus, a position of a beam spot produced on the material 70is controlled. That is, the surface of the material 70 is scanned by theelectron beam, and thus, information is written in a predeterminedposition.

In the above-described electron beam applying apparatus 50 in therelated art, two methods for increasing an amount of an electric currentof the electron beam condensed on the surface of the material 70 can beconsidered, as follows:

As a first method, as shown in FIG. 6, an effective angular aperture ofthe electron beam emitted from the electron source 52 is increased, andalso, an aperture diameter of the selector aperture 60 is increased (thepassage of the electron beam in FIG. 6 is in a zone defined by the innerlines through a zone defined by the outer lines). By increasing theeffective angular aperture of the electron beam emitted from theelectron source 52, more part of the electron beam can be condensed bythe condenser lens 58. Further, by increasing the aperture diameter ofthe selector aperture 60, more part of the electron beam can becondensed by the objective lens 66. Thereby, an amount of electriccurrent of the electron beam condensed on the surface of the material 70can be increased.

However, in this method, the angular aperture of the objective lens 66increases as the aperture diameter of the selector aperture 60 isincreased. As spherical aberration of a lens increases in proportion tothird power of its angular aperture, a shift in the focal pointincreases due to a difference in the electron beam passage condensed onthe surface of the material 70, occurring due to the sphericalaberration of the objective lens 66. Accordingly, it becomes difficultto sufficiently condense the electron beam by means of the objectivelens 66, and thus, it may not be possible to sufficiently reduce thebeam diameter, or the beam diameter of the electron beam increases.

In the second method, as shown in FIG. 7, the angular aperture of theobjective lens 66 is not changed, but the crossover point CP is moveddownward (for example, from CP1 to CP2), and thus, a reduction ratio ofthe beam diameter of the electron beam condensed on the surface of thematerial 70 with respect to the beam diameter of the electron beamemitted from the electron source 52 is lowered (the passage of theelectron beam is, in FIG. 7, in a zone defined by the inner linesthrough a zone defined by the outer lines). By lowering the beamdiameter reduction ratio of the electron beam, the effective angularaperture of the electron beam emitted from the electron source 52increases, and thus, it is possible to increase the electric currentamount of the electron beam condensed on the surface of the material 70.

However, since the beam diameter reduction ratio of the electron beam isthus made smaller, this method can be applied only for a case where thebeam diameter of the electron beam emitted by the electron source 52 isoriginally small, and this method cannot be applied for a case where thebeam diameter is originally large, and thus, the beam diameter should bereduced. Further, as the beam diameter reduction ratio of the electronbeam is thus made smaller, a positional shift of the electron source 52due to a possible vibration, a positional shift of the electron source52 due to a leading voltage (slight voltage shift) or such cannot beignored, and such a positional shift of the electron source 52 may causesomewhat variation in the electron beam condensed on the surface of thematerial 70.

Further, as shown in FIG. 5, in the electron beam applying apparatus inthe related art, generally, the two apertures, i.e., the selectoraperture 60 and the objective aperture 66 are applied. The selectoraperture 60 defines the angular aperture of the electron beam applied tothe condenser lens 58 from the electron source 52, while the objectiveaperture 61 defines the angular aperture of the electron beam applied tothe objective lens 66 from the crossover point CP. That is, the selectoraperture 60 and the objective aperture 61 substantially reduce theelectric current amount of the electron beam condensed on the surface ofthe material 70.

Further, as the two apertures are thus applied, a mechanical error mayoccur therebetween, and the hole parts thereof may not be aligned on thesame axis accurately. Therefore, the hole diameter of the hole part ofthe selector aperture 60 should be enlarged to include this mechanicalerror. However, if the hole diameter of the hole part of the selectoraperture 60 is thus enlarged, the deflection amount of the electron beamfor blanking increases. As a result, a relatively high voltage isrequired as a blanking voltage, and thus, an increase of a turningon/off switching frequency of the electron beam for blanking becomesdifficult. That it, an increase in the drawing speed may not bepossible.

Further, in the electron beam applying apparatus 50 in the related art,as shown in FIG. 5, the blanking electrodes 54 and the axis aligningcoils 56 are disposed in close proximity. Conventionally, since a largeelectric current amount of the electron beam is not required, theelectric current amount flowing through the blanking electrodes issmall. However, when the electric current amount of the electron beam isincreased, a large electric current should be made to flow through theblanking electrodes 54, for the purpose of increasing the turning on/offswitching frequency of the electron beam for blanking.

However, when a large electric current is flown through the blankingelectrodes 54, a magnetic field occurs in the axis aligning coils 56disposed in close proximity thereto. Thereby, the electron beam is bent,and thus, an axis shift may occur in the electron beam.

Further, conventionally, since a large electric current is not requiredfor the electron beam, the crossover point CP is set at a relativelyhigher position. Therefore, the beam diameter reduction ratio of theelectron beam can be set in a relatively large amount. Thereby, evenwhen somewhat axis shift occurs in the axis aligning coils 56, aninfluence of the axis shift of the electron beam condensed on thesurface of the material 70 can be reduced by several times according tothe large reduction ratio. Thus, an influence of the electron beam axisshift in the axis alignment coils 56 does not cause an actual problem.

However, when the crossover point CP is lowered for example as mentionedabove for the purpose of increasing the electric current amount of theelectron beam, the bema diameter reduction ratio of the electron beamlowers. Thereby, an axis shift of the electron beam in the axis aligningcoils 56 may cause a large problem in this case.

As a prior art concerning the present invention, Japanese Laid-openPatent Application No. 6-131706 is cited. This document discloses aninformation recording apparatus producing an original disk of aninformation recording medium such as an optical disk. For example, inFIG. 1 thereof, a configuration is disclosed in which an electronemitted by a filament is made to pass through Welnelt electrode andanode as an electron beam applying tube, after that the electron beam iscondensed by first and second electromagnetic lenses, further,deflection electrodes are applied, and thus, the electron beam isfocused on the original disk serving as a target.

DISCLOSURE OF THE INVENTION

An object of the present invention is to solve the above-mentionedproblems based on the related art, and to provide an electron beamapplying apparatus generating an electron beam having a large electriccurrent and a minimal beam diameter, and making it possible to carry outdrawing at high speed, and a drawing apparatus with the use thereof,with a simple configuration at a low cost.

In order to achieve the object, according to the present invention, anelectron beam applying apparatus for applying an electron beam to asurface of a material for recording information on the surface of thematerial, includes:

a thermal field emission type electron source emitting the electronbeam;

an electrostatic lens, disposed immediately below the electron source,acting as a condensing electrode for condensing the electron beam in afirst angular aperture emitted by the electron source, in a secondangular aperture smaller than the first angular aperture;

a condenser lens disposed on a downstream side of the electrostaticlens, condensing the electron beam once condensed in the second angularaperture by the electrostatic lens, in a crossover point; and

an objective lens disposed on a downstream side of the condenser lens,condensing the electron beam once condensed in the crossover point bythe condenser lens, on the surface of the material.

There, a beam diameter reduction ratio of the electron beam condensed onthe surface of the material with respect to a beam diameter of theelectron beam emitted by the electron source when the electrostatic lensis not applied may be preferably set within a range between 1 and 10.

Further, the beam diameter reduction ratio may be further preferably setapproximately equal to 1.

Further, an axis aligning coil may be disposed between the electrostaticlens and the condenser lens for correcting an axis shift of the electronbeam applied to the condenser lens from the electrostatic lens; and

a blanking electrode may be disposed between the condenser lens and theobjective lens, deflecting the electron beam condensed in the crossoverpoint by the condenser lens.

Further, an aperture acting both as a selector aperture and as anobjective aperture may be disposed between the condenser lens and theobjective lens, on a downstream side of the blanking electrode, forcontrolling turning on/off of the electron beam, together with theblanking electrode, according to information to be written, for a caseof writing the information, and

the crossover point may be set in the vicinity of and on an upstream ora downstream side of a hole part of this aperture.

Further, according to the present invention, a drawing apparatus isconfigured to record information on a surface of a material with the useof an electron beam applied by any one of the above-mentioned electronbeam applying apparatuses according to the present invention.

In the electron beam applying apparatus according to the presentinvention, by disposing the electrostatic lens, the electron beam in arange of the first angular aperture emitted by the electron source isapplied to the condenser lens. Thereby, it is possible to increase anelectric current amount of the electron beam applied to the surface ofthe material.

Further, a beam diameter of the electron beam emitted by the electronsource in the thermal field emission type is in a range between 20 and50 nm, and thus a sufficiently minimal beam diameter is obtained.Accordingly, it is possible to increase the electric current amount ofthe electron beam condensed on the surface of the material by setting abeam diameter reduction ratio of the electron beam to be smaller for acase where the electrostatic lens is not disposed.

Further, by disposing the electrostatic lens, an apparent position ofthe electron source with respect to the condenser lens is more distantthan that of the actual position of the electron source. Accordingly,the beam diameter reduction ratio of the electron beam for the casewhere the electrostatic lens is disposed becomes larger than that of thecase where the electrostatic lens is not disposed. Thereby, an influenceof a possible vibration of the electron source on the electron beamcondensed on the surface of the material is reduced.

Furthermore, since the electron beam applying apparatus according to thepresent invention has a very simple configuration in which the thermalfield emission type electron source is applied, and the electrostaticlens is disposed, it is possible to generate an electron beam with alarge electric current with a minimal beam diameter at a low cost.

Further, by setting the crossover point in the proximity to the holepart of the aperture acting both as the selector aperture and as theobjective aperture, it is possible to reduce the hole diameter of thehole part, and to reduce a deflection amount of the electron beam forblanking. Thereby, it is possible to make the blanking voltagerelatively low, and to increase an electron beam tuning on/off switchingfrequency for blanking. That is, it is possible to achieve high speeddrawing.

Further, in the electron beam applying apparatus according to thepresent invention, the axis aligning coil and the blanking electrode aredisposed apart. Accordingly, even when a large electric current is madeto flow through the blanking electrodes for the purpose of increasingthe electron beam turning on/off switching frequency for blanking, itselectromagnetic interference does not occur in the axis aligning coil.As a result, it is possible to avoid a situation in which magnetic fieldoccurs in the axis aligning coils, the electron beam is bent, and thus,an axis error occurs in the electron beam.

Further, in the drawing apparatus according to the present invention,since information is recorded on a surface of a material with the use ofan electron beam emitted by any one of the above-mentioned electron beamapplying apparatuses, it is possible to carry out, with a simpleconfiguration at a low cost, drawing at high speed with the use of theelectron beam with a large electric current and a minimal beam diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an outline of one embodiment of an electron beam applyingapparatus according to the present invention;

FIG. 2 shows a configuration of an electrostatic lens applied in theelectron beam applying apparatus shown in FIG. 1;

FIG. 3 shows an outline of a state of an electron beam in the electronbeam applying apparatus shown in FIG. 1;

FIG. 4 shows an outline of one embodiment of a drawing apparatusaccording to the present invention;

FIG. 5 shows an outline of one example of an electron beam applyingapparatus in the related art; and

FIGS. 6 and 7 show outlines of states of an electron beam in theelectron beam applying apparatus shown in FIG. 5.

BEST MODE FOR CARRYING OUT THE PRESENT INVENTION

Based on a preferable embodiment shown in figures, an electron beamapplying apparatus and a drawing apparatus employing it according to thepresent invention are described in detail.

FIG. 1 shows an outline of an embodiment of an electron beam applyingapparatus according to the present invention. The electron beam applyingapparatus 10 shown is used to apply an electron beam on a surface of amaterial 32 for the purpose of recording information on the surface ofthe material 32 (for example, an optical medium such as a DVD), andincludes an electron source 12, an electrostatic lens 14, axis aligningcoils 16, a condenser lens 18, blanking electrodes 20, an aperture 22acting both as a selector aperture and as an objective aperture, anastigmatism correction coil 24, electrostatic deflection electrodes 26,an objective lens 28 and a dynamic focal correction lens 30.

In the electron beam applying apparatus 10 shown, the electron source(electron gun) 12 is of a thermal field emission type, and is disposedin an ultra-high vacuum. An electron beam is emitted from the electronsource 12 downward in FIG. 1.

The electron beam emitted by the electron source 12 has a sufficientlyminimal beam diameter, i.e., on the order of a range between 20 and 50nm. Thereby, it is not necessary to set a beam diameter reduction ratioof the electron beam condensed on the surface of the material 32 withrespect to the beam diameter of the electron beam emitted by theelectron source 12 to be large, in terms of obtaining an electron beamhaving a minimal beam diameter. In the case of the present embodiment, asetting is made such that the beam diameter reduction ratio for a casewhere the electrostatic lens 14 is not applied may be approximatelyequal to 1.

The electrostatic lens 14 is made of a condensing electrode condensingthe electron beam in a range of a first angular aperture emitted by theelectron source 12, in a range of a second angular aperture smaller thanthe first angular aperture, and is disposed immediately below theelectron source 12.

In the present embodiment, the electrostatic lens 14 is made of a pairof cylindrical lenses to which different voltages V1 and V2 are applied,respectively. However, the electrostatic lens 14 is not limited thereto,and those of various types may be applied instead.

There, as the condensing electrode, a magnetic lens may be applied.However, when the magnetic lens is applied, a degree of vacuum aroundthe electron source 12 may degrade due to gas emitted by a coil includedin the magnetic lens, and the recording performance of the electron beamapplying apparatus may degrade accordingly. Further, the gas emitted bythe coil is ionized by a magnetic field, the ions hit an emitter of theelectron source, and thus, the life thereof may be shortened. Therefore,the electrostatic lens 14 is applied as the condensing electrode in theelectron beam applying apparatus 10.

Next, the condenser lens 18 is made of an electromagnetic lenscondensing the electron beam condensed in the second angular aperture bymeans of the electrostatic lens 14, in a crossover point CP. Theobjective lens 28 is made of an electromagnetic lens condensing theelectron beam condensed in the crossover point CP by means of thecondenser lens 18, on the surface of the material 32. The dynamic focalcorrection lens 30 is used to correct a focal point of the electron beamto cause it to coincide with the surface of the material 32. Theabove-mentioned condenser lens 18, the objective lens 28 and the dynamicfocal correction lens 30 are disposed in the stated order on adownstream side of the electrostatic lens 14.

The axis aligning coils 16 are disposed between the electrostatic lens14 and the condenser lens 18. The axis aligning coils are used tocorrect an axis shift of the electron beam applied to the condenser lens18 from the electrostatic lens 14.

The blanking electrodes 20, the aperture 22 acting both as the selectoraperture and as the objective aperture, the astigmatism correction coil24 and the electrostatic deflection electrodes 26 are disposed in thestated order between the condenser lens 18 and the objective lens 28.

The blanking electrodes 20 and the aperture 22 acting both as theselector aperture and as the objective aperture are used to control theelectron beam tuning on (writing)/off (stop writing), when writinginformation, according to the information to be written. That is, whendeflection of the electron beam is not carried out by the blankingelectrodes 20, the electron beam is applied (turning on) to the surfaceof the material 32 after passing through the hole part of the aperture22 acting both as the selector aperture and as the objective aperture.On the other hand, as a result of the electron beam being deflected bythe blanking electrodes 20, the electron beam is shut off (turning off)by means of the aperture 22 acting both as the selector aperture and asthe objective aperture.

The astigmatism correction coil 24 is used to correct astigmatism of theelectron beam. The electrostatic deflection electrodes 26 controls aspot position of the electron beam on the surface of the material 32 bydeflecting the electron beam according to information to be written whenthe information is written on the surface of the material 32.

In the electron beam applying apparatus 10 shown in FIG. 1, the electronbeam emitted by the electron source 12 in the range of the first angularaperture is condensed in the range of the second angular aperture bymeans of the electrostatic lens 14; an axis shift of the electron beamis corrected by the axis aligning coils 16; and the electron beam iscondensed in the crossover point CP by means of the condenser lens 18.Then, the electron beam having passed through the hole part of theaperture 22 acting both as the selector aperture and as the objectiveaperture undergoes correction of astigmatism thereof by means of theastigmatism correction coil 24; the focal point of the electron beam iscorrected by the dynamic focal correction lens 30; and the electron beamis condensed on the surface of the material 32.

When information is written, the blanking electrodes 20 and the aperture22 acting both as the selector aperture and as the objective aperturecontrol turning on/off of the electron beam condensed by the condenserlens 18. Further, the electron beam having passed through the hole partof the aperture 22 acting both as the selector aperture and as theobjective aperture and being applied to the objective lens 28 isdeflected by the electrostatic deflection electrodes 26 according to theinformation to be written, and thus, a spot position thereof on thesurface of the material 32 is controlled. That is, the surface of thematerial 32 is scanned by the electron beam, and thus, the informationis written in a predetermined position.

As described above, the beam diameter of the electron beam emitted bythe electron source 12 in the thermal field emission type issufficiently minimal, i.e., on the order of the range between 20 and 50nm. Therefore, the beam diameter of the electron beam condensed on thesurface of the material 32 becomes sufficiently minimal even withoutmaking a setting of the beam diameter reduction ratio of the electronbeam to be large. Accordingly, by making a setting of the beam diameterreduction ratio of the electron beam to be small as in the presentembodiment, it is possible to increase an electric current amount of theelectron beam condensed on the surface of the material 32.

The beam diameter reduction ratio of the electron beam for a case wherethe electrostatic lens 14 is not applied may be preferably set in arange between 1 and 10 in terms of increasing the electric currentamount of the electron beam condensed on the surface of the material 32,and may be most preferably set in approximately 1 as in the presentembodiment.

Further, as mentioned above, in the electron beam applying apparatus 10,the electron beam emitted from the electron source 12 in the range ofthe first angular aperture is condensed in the range of the secondangular aperture by the electrostatic lens 14, and the electron beam isapplied to the condenser lens 18. That is, the electron beam in therange of the first angular aperture emitted by the electron source 12 isapplied to the condenser lens 18. Thereby, it is possible to furtherincrease the electric current amount of the electron beam condensed onthe surface of the material 32.

Further, as shown in FIG. 3, by disposing the electrostatic lens 14, anapparent position of the electron source 12 with respect to thecondenser lens 18 is located more distant than the actual position ofthe electron source 12 (in FIG. 3, apparently, the electron source 12seems to be located higher than the actual position). Accordingly, inthe present embodiment, although the beam diameter reduction ratio ofthe electron beam for the case where the electrostatic lens 14 is notapplied is set in approximately 1, the actual beam diameter reductionratio for the case where the electrostatic lens 14 is applied becomesmore than 1 depending on the first and second angular apertures.

Thus, in comparison to the case where the electrostatic lens 14 is notapplied, the actual beam reduction ratio of the electron beam increasesfor the case where the electrostatic lens 14 is applied. Thereby, aninfluence of a possible vibration of the electron source 12 on theelectron beam condensed on the surface of the material 32 is reduced.Further, since the electron beam applying apparatus 10 has a very simpleconfiguration of employing the electron source 12 in the thermal fieldemission type and disposing the electrostatic lens 14, it is possible togenerate the electron beam of a large electric current with a minimalbeam diameter at a low cost.

Further, as can be seen from a comparison between the electron beamapplying apparatus 10 in the embodiment shown in FIG. 1 and the electronbeam applying apparatus 50 in the related art shown in FIG. 5, only theaperture 22 acting both as the selector aperture and as the objectiveaperture is applied as an aperture in the embodiment of the presentinvention. The aperture 22 acting both as the selector aperture and asthe objective aperture has both functions as the selector apertures 60and the objective aperture 61 of the electron beam applying apparatus 50(The aperture 22 acting both as the selector aperture and as theobjective aperture integrally includes both the functions of theselector apertures 60 and the objective aperture 61).

In the electron beam applying apparatus 10 in the present embodiment,the crossover point CP is set in the vicinity of the hole part of theaperture 22 acting both as the selector aperture and as the objectiveaperture. Thereby, the hole diameter of the hole part of the aperture 22acting both as the selector aperture and as the objective aperture canbe shortened in the order of a range between 40 and 100 μm, for example.When the hole diameter of the hole part of aperture 22 acting both asthe selector aperture and as the objective aperture is thus madesmaller, the deflection amount of the electron beam for blanking can bemade smaller. Thereby, the blanking voltage can be made relativelylower, and the electron beam turning on/off switching frequency forblanking can be increased. That is, drawing can be carried out at highspeed.

In the electron beam applying apparatus 10 in the present embodimentshown in FIG. 1, the crossover point CP is set above, in the vicinity ofthe hole part of the aperture 22 acting both as the selector apertureand as the objective aperture, and the angular aperture of the electronbeam is controlled by the downstream-side (bottom surface side) innercircumferential edge of the hole part of aperture 22 acting both as theselector aperture and as the objective aperture. In contrast thereto,the crossover point CP may be set below, in the vicinity of the holepart of aperture 22 acting both as the selector aperture and as theobjective aperture, and the angular aperture of the electron beam may becontrolled by the upstream-side (top surface side) inner circumferentialedge of the hole part of aperture 22 acting both as the selectoraperture and as the objective aperture.

Further, in the electron beam applying apparatus 10 in the presentembodiment, the axis aligning coils 16 are disposed between theelectrostatic lens 14 and the condenser lens 18, and the blankingelectrodes 20 are disposed between the condenser lens 18 and theobjective lens 28 (between the condenser lens 18 and the aperture 22acting both as the selector aperture and as the objective aperture).That is, the axis aligning coils 16 and the blanking electrodes 20 aredisposed apart. As described above, when the electric current amount ofthe electron beam is increased, a large electric current should be madeto flow through the blanking electrodes 20 for increasing the electrodeturning on/off switching frequency.

In the electron beam applying apparatus 10 in the present embodiment,since both are disposed apart as mentioned above, an electromagneticinfluence of a large electric current flowing through the blankingelectrodes 20 do not occur in the axis aligning coils 16, even when thelarge electric current is made to flow through the blanking electrodes20. As a result, a problematic situation in which an axis shift occursas a result of the electron beam being bent due to a magnetic fieldoccurring in the axis aligning coils 16 can be avoided. Accordingly,even when the crossover point CP is set at a relatively lower position,for example, for the purpose of achieving a large electric current ofthe electron beam, and thus the reduction ratio is made smaller, aninfluence of an axis shift of the electron beam in the axis aligningcoils 16 hardly occurs.

The electron beam applying apparatus 10 shown in FIG. 1 has beendescribed above as one example, and an electron beam applying apparatusaccording to the present invention is not limited to this configuration.For example, in the embodiment of FIG. 1, the condenser lens 18 and theobjective lens 28 are in single stages, respectively. However, eachthereof may be configured in multiple stages. Further, such respectivecomponents as the aperture 22 acting both as the selector aperture andas the objective aperture, the astigmatism correction coil 24, theelectrostatic deflection electrodes 26 and the dynamic focal correctionlens 30 may be applied as the necessary arises, and any other types mayalso be applied instead.

A drawing apparatus according to the present invention is describednext.

FIG. 4 shows an outline of an embodiment of a drawing apparatusaccording to the present invention. The drawing apparatus 11 shown is anelectron beam drawing apparatus recording information on a surface of amaterial 32 with the use of the electron beam applied from the electronbeam applying apparatus 10 shown in FIG. 1. The electron beam drawingapparatus is mounted on a top of a vacuum chamber 71 placed on avibration removing (vibration-free) mechanism (for example, a servomounter with the use of air pressure, or such) not shown, in such amanner that the electron beam emitted by the electron beam applyingapparatus 10 may be applied to the surface (drawing surface) of thematerial 32 approximately perpendicularly.

A substrate 74 is provided inside of the vacuum chamber 71, and, on atop end surface thereof, a movable body 75 is disposed via a rollerbearing 76 in which spherical or cylindrical rollers or such aredisposed in a feeding direction (a direction of an arrow X of FIG. 4).The moveable body 75 is L-shaped in a cross section as shown in FIG. 4,and a screw hole part is produced in a right end part of the movablebody 75. In the screw hole part, a screw hole is provided in which afeeding screw 77 which is a rotation shaft of a feeding driving motor 72described below is fit.

The feeding driving motor 72 is disposed in a bottom right part of thevacuum chamber 71 in FIG. 4, and has the feeding screw 77, such as aball screw, as the rotation shaft thereof. As mentioned above, thefeeding screw 77 is fit in the screw hole of the screw hole part of themovable body 75. That is, a feeding mechanism 78 is configured in which,as a result of the feeding screw being rotated with a power supplysignal not shown to the feeding driving motor 72, the movable body 75 isfreely moved in the arrow X direction (horizontal direction in FIG. 4),in a state in which the material 72 is placed on a rotating table 82described later.

On a top surface of the movable body 75, an air spindle 87 is fixedwhich floats hydrostatically in radial and thrust directions by means ofcompressed air not shown provided externally. On a top side surface ofthe air spindle 87, the rotating table 82 on which the material 72 isplaced is fixed. For a case where the air spindle 87 is provided in areduced pressure (vacuum) condition, a seal mechanism such as a magneticfluid seal, a different pressure air discharging seal or such isprovided in the periphery of the air spindle 87 for achieving a vacuumseal, generally.

In a top left part of the vacuum chamber 71 in FIG. 4, a load lock 84 isdisposed via a stop valve 85. In the load lock 84, a conveyance unit 86for the material 32 is provided. By means of the conveyance unit 86, thematerial 32 is introduced in the vacuum chamber 71, or the material 32is ejected from the vacuum chamber 71. At the bottom of the vacuumchamber 71, a vacuum pump 73 such as a turbo-molecular pump or such isprovided in a communicating condition. During drawing, as describedabove, a vacuum is formed in the vacuum chamber 71 therewith.

Below the air spindle 87, an optical rotary encoder 80 is fixedproviding an output of A phase and B phase pulses generated fromthousands of divisions a turn and a Z phase pulse generated a turn. Thatis, a rotating mechanism 83 is configured for freely rotating the airspindle 87, that is, the rotating table 82 in a direction of rotatingarrow shown in FIG. 4, and thereby, the material 32 is made to freelyturn according to a power supply signal not shown provided to a rotatingdriving motor 81.

When information is recorded on the surface of the material 32, thematerial 32 is introduced in the vacuum chamber 71 by the conveyanceunit 86 in the load lock 84, and is placed on the rotating table 82.Then, the vacuum pump 73 forms a predetermined vacuum condition in thevacuum chamber 71.

When drawing is carried out, the rotating table 82, that is, thematerial 32 is made to turn at a predetermined speed in the rotatingarrow direction, by means of the rotating driving motor 81 and theoptical rotary encoder 80, and also, the material 32 is moved in apredetermined direction along the arrow X direction as a result of thefeeding screw 77 being rotated in a predetermined direction by thederiving motor 72. In this condition, information is recorded on thesurface of the material 32 two-dimensionally by means of the electronbeam emitted by the electron beam applying apparatus 10.

When the drawing is finished, the material 32 is ejected from the vacuumchamber 71 by means of the conveyance unit 86 in the load lock 84.

The description has been made for the drawing apparatus as one example.A drawing apparatus according to the present invention is configured torecord information on a surface of a material with the use of anelectron beam emitted by an electron beam applying apparatus accordingto the present invention, and nothing other than it is limited. Forexample, in the above-described embodiment, the material is made to turnwhile the material is moved in one direction, when drawing is carriedout. However, the material may be moved in two directions, i.e., thearrow X direction and a Y direction perpendicular thereto. Furtheralternatively, drawing may be carried out in a condition in which thematerial is moved in three directions, i.e., XYZ directions including aZ direction which is a vertical direction in FIG. 4.

Further, an electron beam applying apparatus and a drawing apparatusaccording to the present invention may also be applied for recordinginformation to various types of information recording media such as ahologram memory or such, other than recording information to an opticalmedium such as a DVD.

Further, the present invention is not limited to the above-describedembodiments, and variations and modifications may be made withoutdeparting from the basic concept of the present invention claimed inCLAIMS below.

The present application is based on Japanese Priority Applications No.2004-214452, Jul. 22, 2004, the entire contents of which are herebyincorporated herein by reference.

1. An electron beam applying apparatus for applying an electron beam toa surface of a material for recording information on the surface of thematerial, comprising: a thermal field emission type electron sourceemitting an electron beam; an electrostatic lens, disposed immediatelybelow the electron source, acting as a condensing electrode forcondensing the electron beam in a first angular aperture emitted by theelectron source, in a second angular aperture smaller than the firstangular aperture; a condenser lens disposed on a downstream side of theelectrostatic lens, condensing the electron beam once condensed in thesecond aperture angle by the electrostatic lens, in a crossover point;and an objective lens disposed on a downstream side of the condenserlens, condensing the electron beam once condensed in the crossover pointby the condenser lens, on the surface of the material, wherein: a beamdiameter reduction ratio of the electron beam condensed on the surfaceof the material with respect to a beam diameter of the electron beamemitted by the electron source when the electrostatic lens is notapplied is set within a range between 1 and
 10. 2. The electron beamapplying apparatus as claimed in claim 1, wherein: the beam diameterreduction ratio is set approximately equal to
 1. 3. An electron beamapplying apparatus for applying an electron beam to a surface of amaterial for recording information on the surface of the material,comprising: a thermal field emission type electron source emitting anelectron beam; an electrostatic lens, disposed immediately below theelectron source, acting as a condensing electrode for condensing theelectron beam in a first angular aperture emitted by the electronsource, in a second angular aperture smaller than the first angularaperture; a condenser lens disposed on a downstream side of theelectrostatic lens, condensing the electron beam once condensed in thesecond aperture angle by the electrostatic lens, in a crossover point;an objective lens disposed on a downstream side of the condenser lens,condensing the electron beam once condensed in the crossover point bythe condenser lens, on the surface of the material; an axis aligningcoil disposed between the electrostatic lens and the condenser lens forcorrecting an axis shift of the electron beam applied to the condenserlens from the electrostatic lens; and a blanking electrode, disposedbetween the condenser lens and the objective lens, deflecting theelectron beam condensed in the crossover point by the condenser lens. 4.The electron beam applying apparatus as claimed in claim 3, furthercomprising: an aperture acting both as a selector aperture and as anobjective aperture, disposed between the condenser lens and theobjective lens, on a downstream side of the blanking electrode, forcontrolling turning on/off of the electron beam together with theblanking electrode, according to information to be written, for a caseof writing the information, wherein: the crossover point is set in thevicinity of, on an upstream or a downstream side of a hole part of saidaperture.
 5. A drawing apparatus configured to record information on asurface of a material with the use of an electron beam applied by theelectron beam applying apparatus claimed in claim
 1. 6. A drawingapparatus configured to record information on a surface of a materialwith the use of an electron beam applied by the electron beam applyingapparatus claimed in claim
 2. 7. A drawing apparatus configured torecord information on a surface of a material with the use of anelectron beam applied by the electron beam applying apparatus claimed inclaim
 3. 8. A drawing apparatus configured to record information on asurface of a material with the use of an electron beam applied by theelectron beam applying apparatus claimed in claim 4.